Executive Functioning in Young Adults with Sub-Threshold Autism Traits

Background: Recent research (Jobe et al, 2007; Kanne et al., in press) has documented increased psychosocial difficulties in individuals who report higher-than-typical autistic traits but without an Autism Spectrum Disorder (ASD) diagnosis.  Little is known, however, regarding the cognitive profile of this broader autism phenotype.

Objectives: To explore whether individuals who report sub-threshold autistic traits also report cognitive difficulties that are similar to those experienced by individuals with ASD.

Methods: A screening version of the Social Responsiveness Scale (SRS) was administered to over 1800 young adults and used to identify 35 individuals (ages 18-21) reporting greater social difficulties (High Trait Group). Seventy-one individuals reporting minimal difficulties were also identified (Low Trait Group).  Group differences in autistic traits were further confirmed using the Autism Spectrum Quotient, t(104) = 11.0, p < .001.  The groups were matched based on the extent of reported ADHD symptomatology, t(104) < 1, p > .05.  For the present study, we utilized the Behavior Rating Inventory of Executive Function (BRIEF) to evaluate behavioral aspects of executive functioning in both groups.

Results: Overall, individuals in the High Trait Group [mean Global Executive Composite (GEC) = 64.5] reported greater executive difficulties than individuals in the Low Trait Group [mean GEC = 56.2], t(104) = 4.2, p < .001.  Significant group differences (High Trait Group > Low Trait Group) were also found on all BRIEF subscales (e.g., Shift, Initiation, Working Memory, Plan/Organize) and remaining index scores (e.g., Behavior Regulation Index), with the exception of the Inhibit subscale and Organization of Materials subscale, p > .05 in both instances.

Conclusions: Consistent with prior literature documenting executive function impairment in individuals with ASD, we found that individuals with a higher degree of autistic traits (but no ASD diagnosis) reported greater levels of executive difficulty as compared to typical control individuals.  Interestingly, the low and high trait groups did not differ on the inhibitory control scale, an area of functioning that appears to be largely spared in individuals with ASD as well (for exception, see Christ et al., 2007).